"And He said unto them, it is not for you to know the times or the seasons, which the Father hath put in His own power." (Acts 1:7)
I would like to begin by citing Paul's exhortation to "Despise not prophesyings." (1 Thessalonians 5:20) The Rapture is indeed a sensitive topic among modern-day, mainstream Christianity. And while the word 'rapture' is nowhere to be found in any English translation, the idea that Jesus is 'coming back'—in some way, shape and/or form—was introduced by Him initially and filled in by the disciples and Paul. If you have the desire to understand such things (Daniel, Revelation, etc.), I suggest studying it out with the help of the Holy Spirit.
"And while they looked stedfastly toward Heaven as He went up, two men stood by them in white apparel; Which also said, Ye men of Galilee, why stand ye gazing up into Heaven? This same Jesus which is taken up from you into Heaven, shall so come in like manner as ye have seen Him go into Heaven." (Acts 1:10-11)
So what's the big deal? Jesus said "Be ye therefore ready also: for the Son of man cometh at an hour when ye think not." (Luke 12:40)
A cargo cult is a tribe of indiginous, usually island-dwelling people, cut off from developing nations, who, when occupied by missionary or military groups, start a form of worship based on and around the occupiers' technologically advanced accoutrements. When the tribe can't (or refuses to) see that the equipment is something other than supernatural or divine, they form a cult around it and around those who brought it. After the invading group leaves the island, usually having promised another shipment to come, the tribe continues on for years expecting a "delivery from the gods". The "delivery" being nothing more than normal cargo and supplies outfitting the occupiers, etc. What's so sad is that for years, the tribe lives in expectation of something that, not only is viewed incorrectly, but also never coming. The practice was so-named around the time of the First World War and to this day, there are still a few cults scattered around the globe.
"But ye have not so learned Christ;" (Ephesians 4:20)
I can't help but think and feel that non-believers view the Rapture—and the Second Coming—as a widespread form of the "cargo cult": passionate-yet-deluded believers in something that's never, ever going to happen. Even to the point of derision ("Jesus is coming. Look busy") Firstly, as Christians, it should go without saying that we believe that Jesus is returning. Whenever the Father chooses, He's going to tap His Son on the shoulder and say "it's time". As an aside, the study of the "end-times" is called Eschatology. But that's as far as this goes because I'm not here to debate one side over another. The Body of Christ is somewhat divided over the interpretation of scriptures that deal with end-times issues. The only word that I can offer is one of pragmatic hope. Jesus says at the beginning of His Parable of the Talents, "occupy till I come" (Luke 19:13) In other words and expressed in a similar vein: "Whatsoever thy hand findeth to do, do it with thy might;" (Ecclesiastes 9:10) What Solomon here is saying is to do the very best you can in the place you find yourself. The place to which you've been called. And whether or not Jesus comes back tomorrow, or we're all raptured on 12/21/2012 (if you're reading this after that, God bless you), it isn't our place to be overly concerned about such things.
"He hath shewed thee, O man, what is good; and what doth the Lord require of thee, but to do justly, and to love mercy, and to walk humbly with thy God?" (Micah 6:8)
"If I will that he tarry till I come, what is that to thee?" (John 21:23)